System and method for wound healing

ABSTRACT

A system is provided for healing a wound. The system includes a flexible body, a therapeutic agent delivery mechanism, a suction mechanism, and a power source. The flexible body includes a cover film having oppositely disposed first and second surfaces that define a compartment. The compartment includes a first porous material, a second porous material, and at least one electrode disposed therein. The second porous material is disposed between the first porous material and the at least one electrode. The therapeutic agent delivery mechanism and the suction mechanism are fluidly connected to the compartment. The power source is in electrical communication with the at least one electrode.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/260,786, filed Jan. 20, 2010, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 61/145,984, filed Jan. 21,2009 (now Expired). This application incorporates the above-identifiedapplications herein by reference in their entirety and claims priorityto all aforementioned applications for all purposes. This applicationalso claims the benefit of U.S. Provisional Patent Application Ser. No.61/505,586, filed Jul. 8, 2011, the entirety of which is herebyincorporated by reference for all purposes.

TECHNICAL FIELD

The present invention relates generally to a system and method forhealing a wound, and more particularly to an iontophoretic, negativepressure system and method for delivering at least one therapeutic agentto a wound using a controlled, vacuum-assisted approach.

BACKGROUND OF THE INVENTION

Wounds are internal or external bodily injuries or lesions caused byphysical means, such as mechanical, pressure, chemical viral, bacterial,or thermal means, which disrupt the normal continuity of structures.Such bodily injuries include contusions, wounds in which the skin isunbroken, incisions, wounds in which the skin is broken by a cuttinginstrument, and lacerations (e.g., wounds in which the skin is broken bya dull or blunt instrument). Wounds may also be caused by accidents orsurgical procedures, in addition to pathologic conditions that causecutaneous disruption.

When cells are injured or killed as a result of a wound, a wound healingstep is desirable to resuscitate the injured cells and produce new cellsto replace the dead cells. The healing process requires the reversal ofcytotoxicity, the suppression of inflammation, and the stimulation ofcellular viability and proliferation. Wounds require low levels ofoxygen in the initial stages of healing to suppress oxidative damage,and higher levels of oxygen in the later stages of healing to promotecollagen formation by fibroblasts.

One method used to promote the healing process is iontophoresis, whichis a non-invasive technology for delivering nutrients, medicines,vitamins, minerals, therapeutic agents, drugs, or other bioactive agentsusing a small electric current, which causes an electrical field. Ingeneral, delivering such medicaments through iontophoresis involvesapplying an electromotive force that transports ions through the stratumcorneum, the outermost layer of skin, and into the dermis, the innerlayer of skin comprised of connective tissue, blood and lymph vessels,sweat glands, hair follicles, and an elaborate sensory nerve network.This same electromotive force can also transport ions through othersubcutaneous tissue planes, would granulation tissues, and biofilms.

Certain drawbacks exist for using iontophoresis to treat dermatologicalwounds, however. For example, treating wounds (e.g., dermatologicalwounds) using iontophoresis can cause localized pH alterations as aresult of accumulation of electrolysis products and cellular necrosis.The build-up of such products can then shield bacteria, fungi, etc. inthe region from penetration of therapeutic agents to the proper tissuedepth.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a system is providedfor healing a wound of a subject. The system comprises a flexible body,a therapeutic agent delivery mechanism, a suction mechanism, and a powersource. The flexible body includes a cover film having oppositelydisposed first and second surfaces that define a compartment. Thecompartment includes a first porous material, a second porous material,and at least one electrode disposed therein. The second porous materialis disposed between the first porous material and the at least oneelectrode. The therapeutic agent delivery mechanism and the suctionmechanism are in fluid communication with the compartment. The powersource is in electrical communication with the at least one electrode.

According to another aspect of the present invention, a method isprovided for healing a wound. One step of the method includes providinga system comprising a flexible body, a therapeutic agent deliverymechanism, a suction mechanism, and a power source. The flexible bodyincludes a cover film having oppositely disposed first and secondsurfaces that define a compartment. The compartment includes a firstporous material, a second porous material, and at least one electrodedisposed therein. The second porous material is disposed between thefirst porous material and the at least one electrode. The therapeuticagent delivery mechanism and the suction mechanism are in fluidcommunication with the compartment. The power source is in electricalcommunication with the at least one electrode. Next, a wound-contactingportion of the compartment is placed into contact with the wound. Atleast one therapeutic agent is then delivered to the wound, followed byactivation of the suction mechanism to remove at least one of fluid ordebris from the wound. The method is optionally repeated until the woundis sufficiently healed.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to those skilled in the art to which the present inventionrelates upon reading the following description with reference to theaccompanying drawings, in which:

FIG. 1A is a perspective view showing a system for healing a woundconstructed in accordance with one aspect of the present invention;

FIG. 1B is an alternative perspective view of the system in FIG. 1A;

FIG. 1C is a cross-sectional view taken along Line 1C-1C in FIG. 1A;

FIG. 2A is a perspective view taken from one side of the system in FIGS.1A-C;

FIG. 2B is a cross-sectional view taken along Line 2B-2B in FIG. 2A;

FIG. 3A is an exploded perspective view showing a first porous material,a sheet member, a second porous member, and an electrode comprising thesystem in FIGS. 1A-C;

FIG. 3B is an assembled perspective view of the first porous material,the sheet member, the second porous member, and the electrode in FIG.3A;

FIG. 4A is a perspective view showing one configuration of the electrodein FIGS. 3A-B;

FIG. 4B is a perspective view showing another configuration of theelectrode in FIGS. 3A-B;

FIG. 5 is a cross-sectional view of a Venturi valve constructed inaccordance with one aspect of the present invention;

FIG. 6 is a process flow diagram illustrating a method for healing awound according to another aspect of the present invention;

FIG. 7 is a cross-sectional view showing the system of FIGS. 1A-C placedin contact with a wound;

FIG. 8 is a cross-sectional view showing therapeutic agents beingdelivered into the wound in FIG. 7 (indicated by arrows); and

FIG. 9 is a cross-sectional view showing continuous delivery and removalof fluid and/or debris from the wound (indicated by arrows).

DETAILED DESCRIPTION

Unless otherwise defined, all technical terms used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich the present invention pertains.

As used in the context of the present invention, the term “subject” canrefer to any warm-blood organism including, but not limited to, humanbeings, pigs, rats, mice, dogs, goats, sheep, horses, monkeys, apes,rabbits, cattle, etc.

As used herein, the terms “therapeutic agent”, “drug”, “agent”,“chemical compound”, and “chemical substance” can refer to anytherapeutically effective molecule or moiety (i.e., molecules ormoieties that are capable of having a biological effect), such aspharmaceutical agents, drugs, or biological agents.

As used herein, the term “wound” can refer to damage or loss to any oneor combination of skin layers caused by cuts, incisions (includingsurgical incisions), abrasions, microbial infections, diseases ordisorders, necrotic lesions, lacerations, fractures, contusions, burnsand amputations. Non-limiting examples of wounds can include bed sores,thin dermis, bullous skin disease, and other cutaneous pathologies, suchas subcutaneous exposed wounds that extend below the skin into thesubcutaneous tissue. In some instances, a subcutaneous exposed wound maynot affect underlying bones or organs.

As used herein, the terms “treatment” and “treating” can refer toobtaining a desired physiologic, dermatological, or cosmetic effect bythe present invention. The effect may be prophylactic in terms ofcompletely or partially preventing a disease, disorder, or symptomthereof and/or may be therapeutic in terms of a partial or complete curefor a disease, disorder, and/or symptom attributable to the disease ordisorder. Thus, the terms can cover any treatment of a disorder ordisease in a subject, such as: (a) preventing a wound from occurring ina subject that may be predisposed to developing the wound but has notyet been diagnosed as having it; (b) inhibiting a wound, e.g., arrestingits development; and (c) relieving, alleviating, or ameliorating a woundby, for example, causing regression of the wound.

As used herein, the term “cosmetic effect” can refer to any treatment bythe present invention that preserves, restores, bestows, simulates, orenhances the appearance of bodily beauty or appears to enhance thebeauty or youthfulness, specifically as it relates to the appearance oftissue or skin.

As used herein, the terms “healing” and “heal” can refer to improvingthe natural cellular processes and humoral substances of tissue repairsuch that healing is faster, and/or the resulting healed area has lessscaring, and/or the wounded area possesses tissue strength that iscloser to that of uninjured tissue, and/or the wounded tissue attainssome degree of functional recovery. The terms can additionally oralternatively refer to the physiological process wherein a wounded areareturns to an effectively normal state. When the wound is an open wound,for example, healing can refer to the process whereby the skin or mucosare-forms a continuous barrier. The skilled artisan will appreciate that,after healing, the area of the wound may comprise scar tissue that isnot identical to the surrounding tissue.

As used herein, the term “operably connected” can refer to a connectionbetween components or entities whereby the one entity is in some wayattached to a second entity. An operable connection can be directlybetween first and the second entities, for example, through the use ofthreaded fasteners, plastic or metallic tube fittings, nails, chemicaladhesives, tape, weldment, or the like. A direct connection betweenfirst and the second entities can be non-detachable, for example,through the use of chemical adhesives or weldment, or detachable, forexample, through the use of removable fasteners, such as threadedfasteners. Alternatively, an operable connection can be indirectlybetween first and the second entities via one or more intermediateentities.

As used herein, the term “fluid communication” can refer to twochambers, vessels, tanks, or other structures containing a fluid, suchas a liquid or gas, where the fluid-containing structures are connectedtogether (e.g., by a line, pipe or tubing) so that a fluid can flowbetween the two fluid-containing structures. Therefore, two chambersthat are in “fluid communication” can, for example, be connectedtogether by a line between the two chambers, such that a fluid can flowfreely between the two chambers.

As used herein, the term “electrical communication” can refer to theability of a generated electric field to be transferred to, or have aneffect on, one or more components of the present invention. In someinstances, the generated electric field can be directly transferred to acomponent (e.g., via a wire or lead). In other instances, the generatedelectric field can be wireles sly transferred to a component.

The present invention relates generally to a system and method forhealing a wound (e.g., a dermatological or subcutaneous exposed wound),and more particularly to an iontophoretic, negative-pressure system andmethod for delivering at least one therapeutic agent to a wound using acontrolled, vacuum-assisted approach. As representative of one aspect ofthe present invention, FIGS. 1A-C illustrate a system 10 for healing awound 12 (FIG. 7). The present invention can be used to seamlesslycontrol drug flow patterns in and about a wound 12 while also removingunwanted materials from the wound site, such as bacteria and otherdebris. In doing so, the present invention maximizes tissue perfusionand the interaction between therapeutic agents and wound tissue.Although the present invention is described below in terms of treatingdecubital ulcers or “bed sores”, it will be appreciated that any othertype of wound 12 can be treated by the present invention.

One aspect of the present invention includes a system 10 for healing awound 12 in a subject. As shown in FIGS. 1A-C, the system 10 generallycomprises a flexible body 14, a therapeutic agent delivery mechanism 16,a suction mechanism 18, and a power source 20. The flexible body 14 hasa substantially rectangular shape; however, it will be appreciated thatthe shape and dimensions (e.g., length, width, thickness) of theflexible body can be varied (e.g., oval-shaped, square-shaped, etc.)depending upon the particular application of the system 10 (e.g., thedimensions of the wound 12). The flexible body 14 includes oppositelydisposed first and second end portions 22 and 24 and a middle portion 26extending between the first and second end portions. The flexible body14 comprises a cover film having oppositely disposed first and secondsurfaces 28 and 30 that define a compartment 32, which is generallylocated at the middle portion 26. As shown in FIGS. 1A-C, each of thefirst and second end portions 22 and 24 of flexible body 14 has aflattened or planar configuration and is adapted for flush placementagainst the skin 34 (FIG. 7) of a subject. All or only a portion of theflexible body 14 (FIGS. 1A-C) can be made from a medical-grade,biocompatible polymeric material, such as silicon, polyethylene andpoly(methyl methacrylate).

The compartment 32 defined by the first and second surfaces 28 and 30has an egg-shaped or bulbous configuration; however, it will beappreciated that other shapes and configurations are possible. Althoughthe compartment 32 is shown as being generally located at the middleportion 26 of the flexible body 14, it will be appreciated that thelocation of the compartment, as well as the portion of the flexible bodycomprising the compartment, can be varied as needed.

As shown in FIGS. 2A-B, the compartment 32 comprises an upper portion 36and a lower wound-contacting portion 38, each of which is defined by aninner wall 40 and an outer wall 42. At least a portion of thewound-contacting portion 38 is porous and includes a series of outputports 44 and uptake ports 46 that extend between the inner and outerwalls 40 and 42. The dimensions (e.g., diameter, length, etc.) of theoutput and uptake ports 44 and 46 can be varied as needed so that thewound-contacting portion 38 can function, where desired, as arate-controlling membrane. As described in more detail below, the outputand uptake ports 44 and 46 respectively facilitate movement of asolution containing at least one therapeutic agent and debris and/orfluid throughout the compartment 32 and the wound 12.

The compartment 32 includes a first porous material 48 (FIGS. 3A-B), asheet member 50, a second porous material 52, and at least one electrode54 that are snugly disposed therein. As shown in FIGS. 3A-B, each of thefirst and second porous materials 48 and 52 has a substantially toroidalshape and includes a plurality of pores 56 extending therethrough. Thefirst and second porous materials 48 and 52 generally comprise a matrixformed from a sponge or gel (e.g., a hydro-gel). The dimensions of thepores 56 comprising the first porous material 48 can be the less than,the same as, or greater than the dimensions of the pores comprising thesecond porous material 52. Each of the first and second porous materials48 and 52, as well as the sheet member 50 includes a central opening 58that collectively form a channel 60. It will be appreciated that theshape and dimensions (e.g., length, height, thickness) of the first andsecond porous materials 48 and 52, as well as the sheet member 50 can bevaried to ensure a snug fit within the compartment 32.

The material(s) used to form the first and second porous materials 48and 52 can include any one or combination of materials that permit theflow of a fluid and/or debris from a wound 12 therethrough. For example,the first porous material 48 and/or the second porous material 52 can becomprised of a biocompatible, non-biodegradable polymeric material madefrom a homopolymer, a copolymer, straight polymers, branched polymers,cross-linked polymers, stimuli-responsive polymers, or a combinationthereof. Examples of such polymers can include silicone, polyvinylalcohol, ethylene vinyl acetate, polylactic acid, nylon, polypropylene,polycarbonate, cellulose, cellulose acetate, polyglycolic acid,polylactic-glycolic acid, cellulose esters, polyethersulfone, acrylics,their derivatives, and combinations thereof.

The sheet member 50 is disposed between the first and second porousmaterials 48 and 52 and functions as a partition to substantiallyprevent the movement of fluid between the first and second porousmaterials. The sheet member 50 is dimensioned so that the sheet memberextends across substantially the entire upper and lower surfaces 62 and64 of the second and first porous materials 52 and 48, respectively. Thesheet member 50 can be made of a substantially impermeable material,such as a medical-grade polymeric material (e.g., silicon). Compared tothe first and second porous materials 48 and 52, the thickness of thesheet member 50 can be relatively thin. For example, the sheet member 50can have a thin film configuration. In another example, the thickness ofthe sheet member 50 can be less than the thickness of each of the firstand second porous materials 48 and 52.

As shown in FIGS. 3A-B, at least one electrode 54 is disposed about alower surface 66 of the second porous material 52. The at least oneelectrode 54 can comprise any one or combination of electrodes capableof providing an electric field sufficient to motivate at least onetherapeutic agent into a wound 12 and/or tissue surrounding the wound.To ensure proper transmission of electrical energy, the at least oneelectrode 54 includes at least two separate, electrically-conductiveportions or components (not shown in detail) that are biased against oneanother. The at least one electrode 54 can be made from one or acombination of flexible, electrically-conductive materials that arecapable of conducting an electric current. For example, materials usedto form the at least one electrode 54 can include metals or metalalloys, such as platinum, platinum-iridium, stainless steel, gold,copper, gold-plated copper, zinc or the like. Additionally oroptionally, at least a portion of the at least one electrode 54 can beembedded within a polymeric material (or other similar material) (e.g.,silicone) to protect wound tissue from abrasion and promotebiocompatibility and/or electrical conduction.

The at least one electrode 54 can comprise any regularly-shaped,irregularly-shaped, uniform, and/or non-uniform electrode capable ofproviding a uniform or non-uniform electric field sufficient to motivateany polarizable chemical compound, including compounds that aredifficult to polarize, such as non-polar drugs and large moleculecompositions into a wound 12 and/or tissue surrounding a wound. In oneexample of the present invention, the at least one electrode 54 cancomprise a first electrically-conductive material (e.g., a treatmentelectrode) (not shown) and a second electrically-conductive material(e.g., a return electrode) (not shown) that are adapted for motivating,or causing the migration of, ionizable therapeutic molecules viaiontophoresis. In another example of the present invention, the at leastone electrode 54 can comprise an interdigitated electrode (not shown)capable of providing a non-uniform electric field to an area sufficientto induce dielectrophoretic transport of at least one therapeutic agent.

In one example of the present invention, the at least one electrode 54can comprise a lasso-shaped electrode as shown in FIG. 4A.

In another example of the present invention, the at least one electrode54 can comprise two or more independent, electrically-conductive members68 (FIG. 4B) separated by an insulator 70, which includes a series ofpores 72 extending therethrough.

Referring again to FIGS. 1A-C, the system 10 additionally includes atherapeutic agent delivery mechanism 16 that is in fluid communicationwith the compartment 32. The therapeutic agent delivery mechanism 16generally comprises a valve 74 (FIG. 5), a therapeutic agent source 76that is in fluid communication with the valve, and an oxygen source 78that is also in fluid communication with the valve. The therapeuticagent delivery mechanism 16 is fluidly connected to the compartment 32by a first fluid line 80, such as medical-grade tubing. For example, afirst end 82 of the first fluid line 80 is securely connected to a fluidoutput portion 84 of the valve 74, while a second end 86 of the firstfluid line is securely connected to the compartment 32. As shown in FIG.1C, the second end 86 of the first fluid line 80 is securely connectedto the compartment 32 via a cap member 88. The cap member 88 can becomprised of a polymeric material and be affixed (e.g., glued, stapled,stitched, etc.) to the upper portion 36 of the compartment 32. Thesecond end 86 of the first fluid line 80 extends through the inner andouter walls 40 and 42 of the upper portion 36 of the compartment 32,through the cap member 88, and into communication with the channel 60.

The valve 74 comprising the therapeutic agent delivery mechanism 16 caninclude any valve that is capable of controllably mixing oxygen with asolution containing one or more therapeutic agents. In one example ofthe present invention, the valve 74 can comprise a Venturi valve asshown in FIG. 5. The Venturi valve has a T-shaped configuration andincludes a fluid output portion 84, a fluid input portion 90, and anoxygen input portion 92. As noted above, the fluid output portion 84 isin fluid communication with the first end 82 of the first fluid line 80.Additionally, the fluid input portion 90 and the oxygen input portion 92are in fluid communication with the therapeutic agent source 76 and theoxygen source 78, respectively, by separate fluid lines (not shown). TheVenturi valve also includes first and second check valves 94 and 96 foradjusting the flow of oxygen and the solution containing one or moretherapeutic agents, respectively, through the Venturi valve.

The therapeutic agent source 76 can include any container or vesselcapable of retaining and dispensing a volume of the solution containingone or more therapeutic agents. Non-limiting examples of suitablecontainers or vessels can include syringes, bottles, tanks, and vatsthat are optionally connected to a pump (not shown). The therapeuticagent(s) comprising the solution are selected based upon the particulartype (or types) of wound(s) being treated. Examples of therapeuticagents can include dermatological agents, antibacterial agents,antifungal agents, anticonvulsant agents, antihypertensive agents,anticancer agents, immunomodulatory agents, antiviral agents,anesthetics, analgesics, tranquilizers, sedatives, muscle relaxants,non-steroidal anti-inflammatory agents, cosmetic agents, biologics,small molecules, polynucleotides, polypeptides and steroids. Otherexamples of therapeutic agents, such as those that can be used forcosmetic or aesthetic purposes can include botox, botulinum toxin,hyaluronic acid, collagen and elastin.

More specific examples of therapeutic agents can include vitamin A, C, Dor E, alpha-hydroxy acids, such as pyruvic, lactic or glycolic acids,beta-hydroxy acids, caffeine, theobromine, lanolin, vaseline, aloe vera,methyl or propyl parban, pigments, dyes and the like for tattooing andmake-up effects, estrogen, make-up agents, anti-aging agents, pigments,such as iron oxide and titanium oxide for use after dermabrading fortattoo removal, iodine to reduce scar tissue, nutrients, DNA, RNA,corticosteroids and -caine-type compounds, such as lidocaine in baseform, estradiol, progesterone, demegestone, promegestone, testosteroneand their esters, nitro-compounds, such as nitroglycerine and isosorbidenitrates, nicotine, chlorpheniramine, terfenadine, triprolidine,hydrocortisone, oxicam derivatives, such as piroxicam, ketoprofen,mucopolysaccharides, such as thiomucase, buprenorphine, fentanyl and itsanalogs, naloxone, codeine, dihydroergotamine, pizotiline, salbutamol,terbutaline, prostaglandins, such as misprostol and emprostil,omeprazole, imipramine, benzamides, such as metaclopramide, scopolamine,peptides, such as growth releasing factor, epidermal growth factor andsomatostatin, cloidine, dihydroxypyridines, such as nifedipine,verapamil, ephedrine, proanolol, metoprolol, spironolactone, thiazides,such as hydrochlorothiazide, flunarizine, syndone imines, such asmolsiodmine, sulfated polysaccharides, such as heparin fractions, andsalts of such compounds with physiologically acceptable acids and bases.

The oxygen source 78 comprising the therapeutic agent delivery mechanism16 can include any suitable oxygen reservoir, such as a pressurizedtank. The oxygen source 78 can hold 100% pure oxygen or, alternatively,any lesser concentration of oxygen, such as air (e.g., about 20%oxygen).

As shown in FIGS. 1A-C, the system 10 additionally includes a suctionmechanism 18 that is in fluid communication with the compartment 32. Thesuction mechanism 18 can comprise a vacuum source 98 that is in fluidcommunication with the compartment 32 via a second fluid line 100 (e.g.,medical-grade tubing). For example, a first end 102 of the second fluidline 100 is securely connected to the vacuum source 98, while a secondend 104 of the second fluid line is securely connected to thecompartment 32. As shown in FIG. 1C, the second end 104 of the secondfluid line 100 extends through the upper portion 36 of the compartment32 so that the lumen of the second fluid line is in fluid communicationwith the first porous material 48. The second end 104 of the secondfluid line 100 can be affixed to the compartment 32 via any knownmethod, such as gluing, stapling, stitching, etc. The vacuum source 98can include any device or apparatus capable of generating or providingnegative pressure within a portion of the compartment 32. For example,the vacuum source 98 can comprise a pump (not shown). The suctionmechanism 18 can be operated at or below atmospheric pressure (i.e.,negative pressure), and can be applied constantly, periodically, orcyclically. As described in more detail below, the suction mechanism 18can promote wound healing by removing fluid and/or debris thataccumulates at or within the wound 12.

The system 10 also includes a power source 20 that is in electricalcommunication with the at least one electrode 54 and capable ofdelivering an electrical signal to the at least one electrode. The powersource 20 is capable of providing an AC signal, a DC signal, or acombination thereof. In some instances, the power source 20 isconfigured to provide a signal having certain characteristics. Asdescribed below, the certain characteristics can include at least oneorienting frequency and at least one motivating frequency. The powersource 20 can be electrically connected to the at least one electrode 54via a direct electrical link or a wireless link (e.g., an RF link). Asshown in FIGS. 1A-C, for example, proximal and distal ends 106 and 108of an electrical lead 110 can be electrically connected to the powersource 20 and the at least one electrode 54, respectively.

FIG. 6 is a process flow diagram illustrating another aspect of thepresent invention. In FIG. 6, a method 120 is provided for healing awound 12. At Step 122, the method 120 includes providing a system 10 forhealing a wound 12. The system 10 can be identically or similarlyconfigured as the system shown in FIGS. 1A-C. For example, the system 10can comprise a flexible body 14, a therapeutic agent delivery mechanism16, a suction mechanism 18, and a power source 20. It will beappreciated that other medical instruments or apparatus can be used tosupplement one or more steps of the method 120, depending upon theparticular type of wound 12 being treated.

At Step 124, a portion of the system 10 is placed into contact the wound12. The particular placement location, type of therapeutic agent (oragents), and the size and shape of the flexible body 14 will depend uponthe type of wound 12 being treated (e.g., deep or shallow, acute ornon-acute, etc.), the location of the wound, the subject's age, anyunderlying disease(s) or condition(s), as well as other factors. Forexample, application of the system 10 to the wound 12 can be done assoon as possible following an acute injury. Depending upon the type ofinjury, however, application of the system 10 to the wound 12 may beinitiated any time after injury or whenever deemed medically necessary.Before placement of the system 10 at Step 124, cleaning and debridementof the wound 12 may be needed.

As shown in FIG. 7, the wound-contacting portion 38 of the compartment32 is placed into contact with the wound 12 so that the wound-contactingportion partially or completely covers the wound. Where the subject issuffering from a bed sore, for example, the entire surface of the bedsore can be covered by the wound-contacting portion 38. When applyingthe wound-contacting portion 38 to the wound 12, care should be taken toeliminate or reduce the presence of void spaces between the outer wall42 of the wound-contacting portion 38 and the wound, which can result ininadequate treatment at those points.

If it has not been done so already, the suction mechanism 18, the powersource 20, and the therapeutic agent delivery mechanism 16 can beoperably connected with the flexible body 14 (as discussed above). Afterdoing so, the therapeutic agent delivery mechanism 16 is activated sothat a volume of the solution containing the therapeutic agent (oragents) is delivered to the wound 12 at a desired rate and frequency(e.g., continuously, periodically, etc.) (Step 126). As described above,the solution containing the therapeutic agent(s) is simultaneouslyflowed through the valve 74 (e.g., Venturi valve) along with oxygen.Using the first check valve 94, the amount of oxygen mixed with thesolution can be varied as needed. The oxygen content in the solution canbe selectively increased by increasing the flow of oxygen into the valve74. Since oxygen is crucial for wound healing, delivery of more oxygeninto the wound 12 advantageously promotes wound healing. As the solutioncontaining the therapeutic agent(s) is flowed through the first fluidline 80, the solution is delivered into the channel 60 and therebysaturates the second porous material 52.

Next, the power source 20 is activated so that at least one therapeuticagent comprising the solution is motivated into the wound 12 and/or thetissue surrounding the wound (FIG. 8). Activation of the power source 20provides one or more electrical signals to the at least one electrode54, which polarizes the at least one therapeutic agent and causes thepolarized therapeutic agent to be motivated into the wound 12 and/or thetissue surrounding the wound via an electromotive force. Thecharacteristics of the electrical signal(s) (e.g., frequency, voltage,etc.) can be varied as needed, as long as migration of the at least onetherapeutic agent is aided by the electromotive force.

In one example of the present invention, the at least one therapeuticagent can be motivated into the wound 12 and/or the tissue surroundingthe wound via iontophoresis. To deliver the at least one therapeuticagent via iontophoresis, the at least one electrode 54 of the system 10can comprise a treatment electrode and a return electrode. Additionally,the power source 20 can include a low-voltage, DC or AC signal generatorhaving positive and negative terminals (not shown) that are inelectrical communication with the treatment electrode and the returnelectrode, respectively. Activation of the power source 20 will causethe treatment and return electrodes to obtain opposite chargepolarities. The opposite charge polarities will then cause at least onetherapeutic agent to ionize. The ionized therapeutic agent will then bedriven into the wound 12 and/or the tissue surrounding the wound asresult of the repulsive force between the treatment and returnelectrodes. Where the therapeutic agent comprises silver, for example,activation of the power source 20 can cause ionized silver ions tomigrate into the bed sore(s) of the subject and thereby kill anybacteria present therein.

In another example of the present invention, the at least onetherapeutic agent can be motivated into the wound 12 and/or the tissuesurrounding the wound via dielectrophoresis. Dielectrophoresis involvesproviding a non-uniform AC or DC electric field to a compound ortherapeutic agent. The non-uniform electric field, in addition toinducing a dipole in the compound or agent, sets up an electrical fieldgradient that provides an electromotive force on the newly polarizedcompound or agent, the magnitude and direction of which are dependent onseveral factors. A more detailed explanation of dielectrophoresis andits operating principles are disclosed in U.S. patent application Ser.No. 11/874,859 (hereinafter, “the '859 application”) and Ser. No.13/107,582, the entirety of each of which is hereby incorporated byreference.

To deliver the therapeutic agent via dielectrophoresis, the at least oneelectrode 54 of the system 10 can comprise an interdigitated electrode.In general, an interdigitated electrode can include any set of at leasttwo electrodes that contain interwoven projections. For example, theinterdigitated electrode can be comprised of a firstelectrically-conductive member that is separated by an insulator from asecond electrically-conductive member. Each of the first and secondelectrically-conductive members can comprise a “comb” electrode (i.e.,an electrode having a number of relatively long, flat prongs that areevenly spaced) whose prongs are interleaved with one another. Theinterdigitated electrode can additionally include at least one passagesufficient to allow at least one therapeutic agent to pass therethrough.More specific details concerning the design and function ofinterdigitated electrodes are disclosed in the '859 application.

The power source 20 can be activated to send an AC signal having certaincharacteristics to the interdigitated electrode. The power source 20 canbe activated to cycle through at least one decade of frequencies rangingfrom about 0.1 Hz to about 20,000 Hz. For example, an AC signal can havean orienting frequency of about 0.1 Hz to about 100 Hz, a motivatingfrequency of between about 100 Hz and about 20,000 Hz, and an amplitudeof between about 1 V to about 10 V. Additionally, an AC signal can beapplied for between about 1 minute and about 30 minutes. A more specificdescription of the electrical signal and the logic used to modulate theelectrical signal is disclosed in the '859 application.

Application of the electrical signal motivates at least one therapeuticagent into the wound 12 and/or the tissue surrounding the wound. Forexample, application of an AC signal to the interdigitated electrodeprovides a non-uniform electric field that induces a dipole on the atleast one therapeutic agent. This, in turn, sets up an electrical fieldgradient that provides an electromotive force on the newly polarizedtherapeutic agent to drive the agent into the wound 12 and/or the tissuesurrounding the wound.

Either before, simultaneous with, or subsequent to delivery of thesolution containing the therapeutic agent(s), the suction mechanism 18is activated to suction fluid and/or debris from the wound 12 at Step128. In particular, the vacuum source 98 is activated so that negativepressure or suction is created within the first porous material 48. Asshown in FIG. 9, the negative pressure or suction causes fluid (e.g.,solution containing the therapeutic agent(s), blood, puss, etc.) and/ordebris (e.g., bacteria, fungi, scab fragments, cellular debris, etc.) tobe pulled through the uptake ports 46, into the first porous material48, and through the second fluid line 100 into a waste reservoir (notshown).

It is known that operation of conventional electromotive devices (e.g.,iontophoresis and dielectrophoresis devices) can create unwantedlocalized pH alterations at the wound site due to accumulation ofelectrolysis products, cellular necrosis, and build-up of dead tissue.Such alterations can shield microorganisms, such as bacteria and fungifrom delivery of the therapeutic agents and thereby contribute tofurther wound development. By removing unwanted fluid and/or debrisduring treatment, an optimal healing environment is created by themethod 120. Additionally, continuous delivery of the solution containingthe therapeutic agent(s) along with application of negative pressure orsuction advantageously creates a flow pattern (collectively indicated byarrows in FIG. 9) about the wound 12 so that the therapeutic agent(s)can flow all over the wound bed. By manipulating the amount of negativepressure and the flow rate of the solution containing the therapeuticagent(s), the flow pattern created about the wound site can beselectively controlled for optimal tissue perfusion and treatmentefficiency.

As indicated at Step 130 of the method 120, Steps 126 and 128 can beoptionally repeated until the wound 12 is sufficiently healed.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes, and modifications are within the skill of the artand are intended to be covered by the appended claims.

1-14. (canceled) 15: A method for healing a wound, said methodcomprising the steps of: (a) providing a system comprising a flexiblebody, a therapeutic agent delivery mechanism, a suction mechanism and apower source, the flexible body including a cover film having oppositelydisposed first and second surfaces that define a compartment, thecompartment including a first porous material, a second porous material,and at least one electrode disposed therein, the second porous materialbeing disposed between the first porous material and the at least oneelectrode, the therapeutic agent delivery mechanism and the suctionmechanism being in fluid communication with the compartment, the powersource being in electrical communication with the at least oneelectrode; (b) placing a wound-contacting portion of the compartmentinto contact with the wound; (c) delivering at least one therapeuticagent to the wound; and (d) activating the suction mechanism to removeat least one of fluid or debris from the wound; (e) optionally repeatingsteps (c)-(d) until the wound is sufficiently healed. 16: The method ofclaim 15, wherein said step of delivering the at least one therapeuticagent to the wound further comprises the steps of: causing the at leastone therapeutic agent and oxygen to flow through the valve into thecompartment; and activating the power source so that the at least onetherapeutic agent is motivated into the wound. 17: The method of claim16, wherein the at least one therapeutic agent is motivated into thewound via iontophoresis. 18: The method of claim 16, wherein the atleast one therapeutic agent is motivated into the wound viadielectrophoresis. 19: The method of claim 15, wherein said step ofactivating the suction mechanism to remove at least one of fluid ordebris from the wound further comprises activating the vacuum source sothat fluid and/or debris is suctioned through the wound-contactingportion of the compartment. 20: The method of claim 15, wherein steps(b)-(d) create a controlled flow pattern of the at least one therapeuticagent about the wound. 21: The method of claim 12, wherein activation ofthe vacuum source creates negative pressure or suction within the firstporous material.